SEER - Sistemes Elèctrics d'Energia Renovable
http://hdl.handle.net/2117/3862
2017-07-27T08:53:25ZAdaptive vector control based wave-to-wire model of wave energy converters
http://hdl.handle.net/2117/106755
Adaptive vector control based wave-to-wire model of wave energy converters
Mir Cantarellas, Antoni; Remón Rodríguez, Daniel; Zhang, Weiyi; Rodríguez Cortés, Pedro
This study presents a complete wave-to-wire model in which a novel wave energy converter control approach based
on adaptive vector control is introduced. The proposed control for maximum power absorption of the primary resource is
included, as well as the grid interconnection topology and required controllers, needed for processing the power over the entire
wave energy conversion chain. Thanks to the adaptive performance of the proposed controller, maximum energy extraction can
be instantaneously achieved regardless of the current irregular wave characteristics of the resource. Finally, the proposed
electrical configuration arises as a suitable grid interconnection solution, as it not only provides maximum power supply from the
wave energy resource, but it also contributes towards further reducing its output power oscillations.
2017-07-24T12:29:58ZMir Cantarellas, AntoniRemón Rodríguez, DanielZhang, WeiyiRodríguez Cortés, PedroThis study presents a complete wave-to-wire model in which a novel wave energy converter control approach based
on adaptive vector control is introduced. The proposed control for maximum power absorption of the primary resource is
included, as well as the grid interconnection topology and required controllers, needed for processing the power over the entire
wave energy conversion chain. Thanks to the adaptive performance of the proposed controller, maximum energy extraction can
be instantaneously achieved regardless of the current irregular wave characteristics of the resource. Finally, the proposed
electrical configuration arises as a suitable grid interconnection solution, as it not only provides maximum power supply from the
wave energy resource, but it also contributes towards further reducing its output power oscillations.Adaptive vector control of wave energy converters
http://hdl.handle.net/2117/105891
Adaptive vector control of wave energy converters
Mir Cantarellas, Antoni; Remón Rodríguez, Daniel; Rodríguez Cortés, Pedro
Many grid connection concerns, such as maximum power absorption and improved power quality, are increasingly gaining research interest in the wave energy sector, as several wave energy converter (WEC) concepts approach their near-commercial deployments. In this regard, several wave energy control solutions have been proposed without a clear sign of a straightforward preferred candidate. Therefore, this paper aims at contributing to the wave energy field by proposing a novel WEC control concept, based on an adaptive vectorial approach for achieving maximum power absorption of the wave energy resource. Thanks to the adaptive characteristic of the proposed controller, maximum energy extraction can be achieved at any time regardless of the dominant frequency characteristics of the waves. Finally, the proposed vectorial approach further contributes in reducing the large instantaneous power fluctuations when operating at maximum power extraction conditions.
2017-06-27T08:47:33ZMir Cantarellas, AntoniRemón Rodríguez, DanielRodríguez Cortés, PedroMany grid connection concerns, such as maximum power absorption and improved power quality, are increasingly gaining research interest in the wave energy sector, as several wave energy converter (WEC) concepts approach their near-commercial deployments. In this regard, several wave energy control solutions have been proposed without a clear sign of a straightforward preferred candidate. Therefore, this paper aims at contributing to the wave energy field by proposing a novel WEC control concept, based on an adaptive vectorial approach for achieving maximum power absorption of the wave energy resource. Thanks to the adaptive characteristic of the proposed controller, maximum energy extraction can be achieved at any time regardless of the dominant frequency characteristics of the waves. Finally, the proposed vectorial approach further contributes in reducing the large instantaneous power fluctuations when operating at maximum power extraction conditions.Power system stability analysis under increasing penetration of photovoltaic power plants with synchronous power controllers
http://hdl.handle.net/2117/105732
Power system stability analysis under increasing penetration of photovoltaic power plants with synchronous power controllers
Remón Rodríguez, Daniel; Mir Cantarellas, Antoni; Mauricio, J.M.; Rodríguez Cortés, Pedro
The utilisation of renewable sources brings many benefits to electric power systems, but also some challenges such as the impact that renewable power plants employing power electronics have on the grid, which is gaining importance as the penetration of this type of generating stations increases, driven by the construction of large wind or solar photovoltaic (PV) power plants. This study analyses the impact of large-scale PV power plants on a transmission grid for different penetration levels. The analysis considers power plants formed by a number of power converters employing synchronous power controllers (SPCs), that allow them to have a harmonious interaction with the grid, and compares their performance with that of conventional power converter controllers, assuming in both cases that the power plants participate in frequency and voltage regulation. The study addresses both the small-signal stability of the system and its response to large disturbances that alter the active power balance and frequency stability. The results of the analysis show that PV power plants using SPCs are able to limit frequency deviations, improve the oscillation damping, and reduce the stress of other generating units, thus having a beneficial impact on the power system.
2017-06-22T10:55:21ZRemón Rodríguez, DanielMir Cantarellas, AntoniMauricio, J.M.Rodríguez Cortés, PedroThe utilisation of renewable sources brings many benefits to electric power systems, but also some challenges such as the impact that renewable power plants employing power electronics have on the grid, which is gaining importance as the penetration of this type of generating stations increases, driven by the construction of large wind or solar photovoltaic (PV) power plants. This study analyses the impact of large-scale PV power plants on a transmission grid for different penetration levels. The analysis considers power plants formed by a number of power converters employing synchronous power controllers (SPCs), that allow them to have a harmonious interaction with the grid, and compares their performance with that of conventional power converter controllers, assuming in both cases that the power plants participate in frequency and voltage regulation. The study addresses both the small-signal stability of the system and its response to large disturbances that alter the active power balance and frequency stability. The results of the analysis show that PV power plants using SPCs are able to limit frequency deviations, improve the oscillation damping, and reduce the stress of other generating units, thus having a beneficial impact on the power system.Frequency support properties of the synchronous power control for grid-connected converters
http://hdl.handle.net/2117/103395
Frequency support properties of the synchronous power control for grid-connected converters
Zhang, Weiyi; Remón Rodríguez, Daniel; Rocabert Delgado, Joan; Luna Alloza, Álvaro; Candela García, José Ignacio; Rodríguez Cortés, Pedro
Grid-connected converters with primary frequency control and inertia emulation have emerged and are promising for future renewable generation plants because of the contribution in power system stabilization. This paper gives a synchronous active power control solution for grid-connected converters. As design considerations, the virtual angle stability and transient response are both analyzed, and the detailed implementation structure is also given without entailing any difficulty in practice. The analysis and validation of frequency support characteristics are particularly addressed. The 10 kW simulation and experimental frequency sweep tests on a regenerative source test bed present good performance of the proposed control in terms of showing inertia and droop characteristics, and the controllable transient response is also demonstrated.
2017-04-05T15:16:29ZZhang, WeiyiRemón Rodríguez, DanielRocabert Delgado, JoanLuna Alloza, ÁlvaroCandela García, José IgnacioRodríguez Cortés, PedroGrid-connected converters with primary frequency control and inertia emulation have emerged and are promising for future renewable generation plants because of the contribution in power system stabilization. This paper gives a synchronous active power control solution for grid-connected converters. As design considerations, the virtual angle stability and transient response are both analyzed, and the detailed implementation structure is also given without entailing any difficulty in practice. The analysis and validation of frequency support characteristics are particularly addressed. The 10 kW simulation and experimental frequency sweep tests on a regenerative source test bed present good performance of the proposed control in terms of showing inertia and droop characteristics, and the controllable transient response is also demonstrated.Frequency support characteristics of grid-interactive power converters based on the synchronous power controller
http://hdl.handle.net/2117/102139
Frequency support characteristics of grid-interactive power converters based on the synchronous power controller
Zhang, Weiyi; Remón Rodríguez, Daniel; Rodríguez Cortés, Pedro
Grid-interactive converters with primary frequency control and inertia emulation have emerged and are promising for future renewable generation plants because of the contribution in power system stabilization. This paper gives a synchronous active power control solution for gridinteractive converters , as a way to emulate synchronous generators for inerita characteristics and load sharing. As design considerations, the virtual angle stability and transient response are both analyzed, and the detailed implementation structure is also given without entailing any difficulty in practice. The analytical and experimental validation of frequency support characteristics differentiates the work from other publications on generator emulation control. The 10 kW simulation and experimental frequency sweep tests on a regenerative source test bed present good performance of the proposed control in showing inertia and droop characteristics, as well as the controllable transient response.
2017-03-08T14:09:57ZZhang, WeiyiRemón Rodríguez, DanielRodríguez Cortés, PedroGrid-interactive converters with primary frequency control and inertia emulation have emerged and are promising for future renewable generation plants because of the contribution in power system stabilization. This paper gives a synchronous active power control solution for gridinteractive converters , as a way to emulate synchronous generators for inerita characteristics and load sharing. As design considerations, the virtual angle stability and transient response are both analyzed, and the detailed implementation structure is also given without entailing any difficulty in practice. The analytical and experimental validation of frequency support characteristics differentiates the work from other publications on generator emulation control. The 10 kW simulation and experimental frequency sweep tests on a regenerative source test bed present good performance of the proposed control in showing inertia and droop characteristics, as well as the controllable transient response.Dynamics estimation and generalized tuning of stationary frame current controller for grid-tied power converters
http://hdl.handle.net/2117/102138
Dynamics estimation and generalized tuning of stationary frame current controller for grid-tied power converters
Zhang, Weiyi; Remón Rodríguez, Daniel; Mir Cantarellas, Antoni; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
The integration of AC-DC power converters to manage the connection of generation to the grid has increased exponentially over the last years. PV or wind generation plants are one of the main applications showing this trend. High power converters are increasingly installed for integrating the renewables in a larger scale. The control design for these converters becomes more challenging due to the reduced control bandwidth and increased complexity in the grid connection filter. A generalized and optimized control tuning approach for converters becomes more favored. This paper proposes an algorithm for estimating the dynamic performance of the stationary frame current controllers, and based on it a generalized and optimized tuning approach is developed. The experience-based specifications of the tuning inputs are not necessary through the tuning approach. Simulation and experimental results in different scenarios are shown to evaluate the proposal.
2017-03-08T14:03:24ZZhang, WeiyiRemón Rodríguez, DanielMir Cantarellas, AntoniLuna Alloza, ÁlvaroRodríguez Cortés, PedroThe integration of AC-DC power converters to manage the connection of generation to the grid has increased exponentially over the last years. PV or wind generation plants are one of the main applications showing this trend. High power converters are increasingly installed for integrating the renewables in a larger scale. The control design for these converters becomes more challenging due to the reduced control bandwidth and increased complexity in the grid connection filter. A generalized and optimized control tuning approach for converters becomes more favored. This paper proposes an algorithm for estimating the dynamic performance of the stationary frame current controllers, and based on it a generalized and optimized tuning approach is developed. The experience-based specifications of the tuning inputs are not necessary through the tuning approach. Simulation and experimental results in different scenarios are shown to evaluate the proposal.A comparative study of methods for estimating virtual flux at the point of common coupling in grid connected voltage source converters with LCL filter
http://hdl.handle.net/2117/101896
A comparative study of methods for estimating virtual flux at the point of common coupling in grid connected voltage source converters with LCL filter
Roslan, Nurul Fazlin; Suul, Jon Are; Luna Alloza, Álvaro; Rocabert Delgado, Joan; Candela García, José Ignacio; Rodríguez Cortés, Pedro
Grid connected Voltage Source Converters (VSCs) with LCL filters usually have voltage measurements at the filter capacitors, while it can be important to control the active or reactive power injection at the grid-side of the LCL filter, for instance at a Point of Common Coupling (PCC). Synchronization to the PCC voltage can be obtained by Virtual Flux (VF) estimation, which can also allow for voltage sensor-less operation of VSCs. This paper is presenting a comparative evaluation of methods for estimating the VF at the PCC, considering a VSC connected to the grid through an LCL filter with a Proportional Resonant (PR) controller as the inner current control loop. The VF estimation is achieved by using frequency adaptive dual SOGI-QSGs (DSOGI-VF). The Frequency Locked Loop (FLL) is used in order to keep the positive and negative sequence (PNS) VF estimation inherently frequency adaptive. Three different methods are considered for obtaining the capacitor current needed for estimating the VF at the grid side of the LCL filter which are based on fully estimation by using the voltage sensor-less method, by estimating the capacitor current from the measured voltage or by using additional capacitor current sensors. The results have been compared and validated by simulation studies.
2017-03-03T09:18:11ZRoslan, Nurul FazlinSuul, Jon AreLuna Alloza, ÁlvaroRocabert Delgado, JoanCandela García, José IgnacioRodríguez Cortés, PedroGrid connected Voltage Source Converters (VSCs) with LCL filters usually have voltage measurements at the filter capacitors, while it can be important to control the active or reactive power injection at the grid-side of the LCL filter, for instance at a Point of Common Coupling (PCC). Synchronization to the PCC voltage can be obtained by Virtual Flux (VF) estimation, which can also allow for voltage sensor-less operation of VSCs. This paper is presenting a comparative evaluation of methods for estimating the VF at the PCC, considering a VSC connected to the grid through an LCL filter with a Proportional Resonant (PR) controller as the inner current control loop. The VF estimation is achieved by using frequency adaptive dual SOGI-QSGs (DSOGI-VF). The Frequency Locked Loop (FLL) is used in order to keep the positive and negative sequence (PNS) VF estimation inherently frequency adaptive. Three different methods are considered for obtaining the capacitor current needed for estimating the VF at the grid side of the LCL filter which are based on fully estimation by using the voltage sensor-less method, by estimating the capacitor current from the measured voltage or by using additional capacitor current sensors. The results have been compared and validated by simulation studies.Control of VSC-HVDC with electromechanical characteristics and unified primary strategy
http://hdl.handle.net/2117/101875
Control of VSC-HVDC with electromechanical characteristics and unified primary strategy
Zhang, Weiyi; Rouzbehi, Kumars; Candela García, José Ignacio; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
High voltage dc (HVDC) systems act as the prevailed solution for transmitting offshore wind energy to onshore main grids. Control of the voltage source converters (VSC) in HVDC systems is decisive for the performance. This paper proposes the control of VSC-HVDC with electromechanical characteristics and unified primary strategy, as a reaction to the updated requirements of the ac grid transmission system operators. As two important aspects of VSC-HVDC control, converter control and primary control are both designed in detail. Electromechanical characteristics make the VSC capable of providing inertia to the ac networks as well as simplicity in island operation. Besides, unified primary control is given as a universal primary strategy for VSC stations, and especially takes into account frequency support and control mode transition. The proposed converter control is validated in scaled-down 10 kW laboratory setups, while the proposed primary control is endorsed by the simulation tests on a CIGRE multi-terminal HVDC model.
2017-03-02T16:07:35ZZhang, WeiyiRouzbehi, KumarsCandela García, José IgnacioLuna Alloza, ÁlvaroRodríguez Cortés, PedroHigh voltage dc (HVDC) systems act as the prevailed solution for transmitting offshore wind energy to onshore main grids. Control of the voltage source converters (VSC) in HVDC systems is decisive for the performance. This paper proposes the control of VSC-HVDC with electromechanical characteristics and unified primary strategy, as a reaction to the updated requirements of the ac grid transmission system operators. As two important aspects of VSC-HVDC control, converter control and primary control are both designed in detail. Electromechanical characteristics make the VSC capable of providing inertia to the ac networks as well as simplicity in island operation. Besides, unified primary control is given as a universal primary strategy for VSC stations, and especially takes into account frequency support and control mode transition. The proposed converter control is validated in scaled-down 10 kW laboratory setups, while the proposed primary control is endorsed by the simulation tests on a CIGRE multi-terminal HVDC model.Control of D-STATCOM during unbalanced grid faults based on DC voltage oscillations and peak current limitations
http://hdl.handle.net/2117/101869
Control of D-STATCOM during unbalanced grid faults based on DC voltage oscillations and peak current limitations
Khoshooei, Arash; Moghani, Javad S.; Milimonfared, Jafar; Luna Alloza, Álvaro; Candela García, José Ignacio; Rodríguez Cortés, Pedro
The safe operation of grid connected power converters during abnormal condition is a key issue in order to guarantee its operation and to avoid undesired trips. In this paper different control methods for the operation of a D-STATCOM are evaluated, where the reference currents are determined in such a way that none of the phase currents goes over the limits, as well as the DC voltage fluctuations remain in safe operation limit. Therefore, the contribution of this paper lays on the combination of the DC voltage oscillations and the current limit control. As it is shown in the following, three different control strategies are evaluated. The amplitude of the oscillations which are superimposed on the DC voltage as well as peak amplitude of the phase currents are calculated for each, considering a generic imbalance in the network. The effectiveness of the presented control strategies are verified by simulating a D-STATCOM tied to an industrial distribution network. Moreover a scaled scenario has been reproduced experimentally which shows that the results cope well with the analytical equations and the simulation results.
2017-03-02T15:47:38ZKhoshooei, ArashMoghani, Javad S.Milimonfared, JafarLuna Alloza, ÁlvaroCandela García, José IgnacioRodríguez Cortés, PedroThe safe operation of grid connected power converters during abnormal condition is a key issue in order to guarantee its operation and to avoid undesired trips. In this paper different control methods for the operation of a D-STATCOM are evaluated, where the reference currents are determined in such a way that none of the phase currents goes over the limits, as well as the DC voltage fluctuations remain in safe operation limit. Therefore, the contribution of this paper lays on the combination of the DC voltage oscillations and the current limit control. As it is shown in the following, three different control strategies are evaluated. The amplitude of the oscillations which are superimposed on the DC voltage as well as peak amplitude of the phase currents are calculated for each, considering a generic imbalance in the network. The effectiveness of the presented control strategies are verified by simulating a D-STATCOM tied to an industrial distribution network. Moreover a scaled scenario has been reproduced experimentally which shows that the results cope well with the analytical equations and the simulation results.Advanced control of a high power converter connected to a weak grid
http://hdl.handle.net/2117/101726
Advanced control of a high power converter connected to a weak grid
Shahparasti, Mahdi; Catalán, Pedro; Candela García, José Ignacio; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro
This paper addresses the stability problems of a high power converter connected to a weak grid. The wide range values that grid impedance can take, challenges the stability and the performance of the controllers, which are responsible of regulating the current injection in such converters. In this work, a control strategy based on stationary reference frame controllers is selected and implemented using a proportional resonant (PR) controller, with capacitor voltage feedforward and a phase shifter. As it will be demonstrated in this paper, although the feedforward contributes to enhance the transient response of the converter, it may cause also deep unstable dynamics near to the medium frequency and decreases the phase margin in low frequency ranges. Therefore, it can be used to damp the unstable dynamics near to resonance frequency range and the LCL-filter can be adopted for the high frequency one. In order to improve the controller performance, a new phase shifter is added to the control scheme to enhance the phase margin at low frequency ranges. Simulation and experimental results considering weak grid conditions are shown to validate the proposed method.
2017-02-28T17:18:06ZShahparasti, MahdiCatalán, PedroCandela García, José IgnacioLuna Alloza, ÁlvaroRodríguez Cortés, PedroThis paper addresses the stability problems of a high power converter connected to a weak grid. The wide range values that grid impedance can take, challenges the stability and the performance of the controllers, which are responsible of regulating the current injection in such converters. In this work, a control strategy based on stationary reference frame controllers is selected and implemented using a proportional resonant (PR) controller, with capacitor voltage feedforward and a phase shifter. As it will be demonstrated in this paper, although the feedforward contributes to enhance the transient response of the converter, it may cause also deep unstable dynamics near to the medium frequency and decreases the phase margin in low frequency ranges. Therefore, it can be used to damp the unstable dynamics near to resonance frequency range and the LCL-filter can be adopted for the high frequency one. In order to improve the controller performance, a new phase shifter is added to the control scheme to enhance the phase margin at low frequency ranges. Simulation and experimental results considering weak grid conditions are shown to validate the proposed method.